This program prepares scientists for research careers in the computational and mathematical modeling of medically significant biological systems through interdisciplinary training at the predoctoral level. Noted for its well-established system f interdisciplinary graduate programs and for its tradition of collaborations across departmental boundaries, the University of Arizona provides a highly suitable environment for such training. Eighteen training faculty and three associate faculty with appointments in multiple departments and interdisciplinary graduate programs provide strength in five broad areas: bioinformatics; molecular dynamics; cellular processes; physiology and pathophysiology; biostatistics and stochastic processes. Students are drawn from multiple graduate programs in mathematical and life sciences, including the interdisciplinary Graduate Program in Applied Mathematics. In most cases, students receive two years of support from this program, starting in their second or third year of graduate training. Trainees pursue the coursework requirements of their own graduate programs and, in addition, take graduate courses in mathematical modeling and in bioinformatics, which are tailored to the trainees' needs and take into account their diverse scientific backgrounds. All trainees take part in a weekly biomathematics colloquium that has been running continuously for more than fifteen years. This colloquium includes presentations by students, faculty and visiting speakers, and promotes dialog between trainees and faculty with primarily mathematical or computational backgrounds and those with strong biological training. Trainees carry out their doctoral research with advisors whose research, whether theoretical or experimental, emphasizes application of theoretical approaches to biomedical problems. Where appropriate, a co-advisor is appointed to provide complementary expertise to that of the primary advisor. Trainees participating in this program not only receive research training in relevant areas, but, equally importantly, develop the ability to communicate and collaborate across traditional disciplinary boundaries and to work with researchers with complementary expertise. Researchers with such skills are critically needed in many areas of biomedical science in which sophisticated theoretical approaches are necessary in order to achieve further progress.